1. Machining Recommendations for C69300 & C87850
Larry Muller
Director of Metallurgy and Technical Services
Chase Brass and Copper Co., LLC.
Montpelier, OH
Confidential – do not distribute without permission
Version: 4/4/17

2. Physical properties related to machining and product performance
ECO BRASS® lead-free copper alloy is produced to established ASTM specifications. Each ECO BRASS customer must thoroughly test and evaluate the material to determine if it is the right alloy for their specific application. Lead-free alloys have different characteristics and properties than traditional leaded alloys and must be evaluated for suitability for each application.
Chase Brass does not warrant the suitability of ECO BRASS® lead-free alloy for any specific application.
Property
Impact
ECO BRASS
C360
303 Stainless
Tensile Strength (ksi)
Turning forces, heat buildup
99.8
76.7
87.3
Work Hardening Coefficient
Thread rolling, knurling
0.13
0.11
0.31
Thermal Conductivity (Btu/ft2/ft/hr/ºF)
Heat removal from drilled holes, tool breakdown
21.8 67
8.8
Version: 4/4/17

3. Recommendations for turning and form tools to increase productivity
Limiting factors (compared to C360):
Higher strength, lower thermal conductivity, multiple phases with different hardness levels
Counter with:
Higher grade of HSS such as T-15 vs. M-2
Carbide with high temperature ceramic coatings e.g. TiAlN
Larger top rake (e.g º) and clearances for 1215 ;
Start skive tool at 20° draft and clearance
Lower rpm (350 sfpm), higher feed rate (≥0.010 ipr)
Minimum dwell time
ECO BRASS vs C360 is analogous to stainless steel vs alloy steel or 1215 vs. 12L14
General comments:
1) parameters are part and machine specific; common problems are sfpm are too high while feed rate is too low
2) Failure to consider these properties of ECO BRASS® lead-free brass may result in excessive heat or stress during machining that can lead to embrittlement or other flaws in the machined parts, possibly leading to failure of the parts.
Version: 4/4/17

4. Recommendations for turning and form tools to increase productivity
Depth of cut
/mm
Feed /mm/rev Cutting speed:100m/min.
Feed /mm/rev Cutting speed:200m/min.
Feed rate (ipr) RPM = 325
Depth of Cut
0.007”
0.020”
0.060”
0.120”
Depth of Cut
0.007”
0.020”
0.060”
0.120”
Feed rate (ipr) RPM = 650
Best feed rates to produce small chips are ≥ ipr.
Chase recommends a minimum of ipr.
Version: 4/4/17

5. Recommendations for deep hole drilling to increase productivity
Limiting factors (compared to C360):
Slightly larger type 1 chips can cause clogging,
Lower thermal conductivity results in heating that will collapse the hole diameter
Counter with:
Higher helix angle
Increased flute width, thin web
Increase the number of flutes (to decrease how much is removed per flute)
Lower rpm, higher feed rate than C360 (start at ipr), 350 sfpm
Clearances like 1215 to reduce frictional heating (higher back taper)
Carbide insert drills (such as Allied)
Through-drill coolant
General comments:
1) Parameters are part and machine specific; common problems are sfpm are too high while feed rate is too low
2) Failure to consider these properties of ECO BRASS® lead-free brass may result in excessive heat or stress during machining that can lead to embrittlement or other flaws in the machined parts, possibly leading to failure of the parts.
Version: 4/4/17

6. Relationship between feed rate and rpm on chip size for deep hole drilling
Feed Rate (ipr)
Drilling speed (fpm)
130
200
260
325
Best feed rate to produce small chips and get best productivity is ≥ ipr
Version: 4/4/17

7. Recommendations for producing threads
Thread chasing –
+3° clearance
Thread milling –
Thread whirling
Female threaded parts must have adequate wall thickness to account for excessive hoop stress generated during installation and ongoing use. Each ECO BRASS customer should perform stress testing for its specific application for all threaded applications.
Version: 4/4/17

8. } Summary of Recommended Machining Practices Compared to C360:
Increase feed rate
Decrease speed
Use positive clearances and rake angle (like steel machining)
Use higher grade of HSS or switch to ceramic coated carbide
Potential for shorter tool life by up to 30% and higher tool forces }
Decreases chip size and frictional heating
Version: 4/4/17